1. Field of the Invention
The present invention relates to a mucoid exopolysaccharide isolated from a particular strain of Pseudomonas aeruginosa, to a method of using this compound, and to a general method capable of isolating this compound.
2. Description of the Prior Art
Pseudomonas aeruginosa infection is a particularly important problem for patients with cystic fibrosis since more than 70% of patients with cystic fibrosis harbor P. aeruginosa in their lungs. Up to 90% of cystic fibrosis patients who survive to adulthood will have had chronic obstructive bronchitis associated with P. aeruginosa at some time during their lives.
Most of the strains of pseudomonas bacteria isolated from patients with cystic fibrosis produce a peculiar polysaccharide slime-like material that has been characterized as a polymer of uronic acids. These so-called "mucoid" pseudomonas strains are considered virtually pathognomonic of cystic fibrosis when isolated from a patient with bronchitis. Production of this slime coating is observed among only one to two percent of pathogenic pseudomonas isolates from other sources. The slime coating, which makes removal of the bacterial colonies difficult, is believed to contribute to the persistence of these slime-generating pseudomonas strains in the lungs of patients with cystic fibrosis.
Various polysaccharides have previously been used to induce immune responses in animals. These include certain mucoid exopolysaccharide from pseudomonas strains (Macone, Pier, et al, N. Engl. J. Med., 304, 1445-1449 (1981)). However, all of the previous mucoid exopolysaccharide isolates were not of general use as a vaccine against all strains of Pseudomonas aeruginosa because of strain specificity of the immunogenic response. Accordingly, a mucoid exopolysaccharide vaccine capable of inducing a vigorous immune response against multiple strains of Pseudomonas aeruginosa is still needed.